Hydrocarbon oil conversion



. May 1s, 1939. 'c p, DUBBS y2,158,962

lI'IYDRGARBON OIL CONVERSION original Filed March 7,".1927

fyi/mei' IEEE/12F Patented May 16, 1939 UNITED STATES PATENT OFFICEHYDROCABBON OIL CONVERSION ware Application March 7, 1927, Serial No.173,269 g Renewed May 7, 1937 4 Glaims. (Cl. 196-49) 'Ihe presentimprovements relate more particul-arly to the conversion of hydrocarbonoils under cracking conditions of conversion temperature andsuperatmospheric pressure. f The invention is characterized primarily byits flexibility, permitting either a high yield of gasoline-likeproducts and a low yield of non-vaporous residue, or a low yield ofgasoline-like products and a large yield of non-vaporous residuum,including the ranges therebetween. l

In different parts` of the world, and particularly in the United States,different market cony ditions prevail, making it advisable from aneconomic standpoint in oner locality to produce a large yield ofgasoline-like products and a low yield of residue suitable for fuel.Conditions in another part of the country may be directly the opposite,and it may be advisable to produce a highyield of residue suitable foruse as fuel.

The present invention has been particularly designed to permit astandard process and apparatus to be utilized `in different parts of thecountry and operated under widely variant conditions. The invention isfurther characterized by its ability to satisfactorily operate ondifierent kinds of charging stock, embracing a range from heavy residueof low Baum gravity up to and including kerosene-like material having arelatively high gravity, say 40 Baume, more or less. It is well knownthat different operating conditions must prevail for different types ofcharging stock, depending on the products desired, and the Apresentinvention has been particularly designed to embrace in a single unit,process and apparatus which would operate efficiently under all thesewidely' variant conditions.

The utility, as well as many other objects and advantages, will be moreapparent from the following description.

In the drawing, the single figure is a diagrammatic or schematic view orflow-chart illustrating the invention.

In the drawing, the charging stock is fed from the charging stockstorage receptacle I through the line 2, in which may beinterposed apump 3, meter 4 and valve 5. When the valve k5 is opened, the oil passesup through the line 2 into a closed coil 6, positioned in the upper partof a dephlegmator 1. This coil 6 may be by-passed if desired by closing'the valves 8 and opening the valve 9 in the by-pass line I0. In eitherevent, lthe charging stock is eventually delivered to the yreturn lineII', in which maybe interposed a valve I2. This return line YII passesthe oil through a closed coil I3, positioned in a heat exchanger I4,from which it may pass through a line I5, controlled by valves I6 and I1into a vapor separator I8. As a feature of the invention, this vaporseparator may preferably comprise a nar- 5 row vertically disposedchamber, having a very limited capacity, wherein vapors that may beformed in the pre-heated charging stock may be released, passing throughthe vapor line I9, controlled by valve 20, into the interior of the 10dephlegmator 1. Vapors thus formed, which, of course, comprise the lowboiling constituents of the charging stock, are thus conveyed directlyinto the dephlegmator 1 and are not forced into the suction of the hotoil pump.

The unvaporized portion is removed from the vapor separator I8 throughthe line 2l, in which may be interposed the hot oil pump 22, said line2l forwarding the pre-heated charging stock t0 the heating tube 23,mounted in a furnace 24. H In passing through the heating tube 23, thecharging stock is raised to a conversion temperature, which, dependingupon the condition of operation', may vary widely from '150 to 1000 F.,more or less. The heated oil is transferred through the transfer line25, in which may be interposed a valve 26, into a reaction chamber 21,where vapor separation takes place. The heating tube 23 and reactionchamber 21 are maintained under a relatively high superatmosu pheriepressure, for instance, from 100 to 30,00 pounds, more or less. 'Ihevapors separating in the reaction chamber 21 pass out through vaporoutlet line 28, controlled by valve 29, being introduced into the lowersection of the dephlegmator 1 below the partition 30 and above thepartition 3|, the vapors passing from this compartment through theopen-ended uprights '32 into the interior of the dephlegmator 1, wherethey are subjected to the usual reflux condensing action, being cooledby means of the charging stock, which may or may not be introducedthrough the coil 6 or by returning regulated portions of the distillateintroduced through the line 33, as will shortly be explained. 'I'hevapors remaining uncondensed after passage through the dephlegmator passout through the vapor outlet line 34, in which may be interposed a valve35, being condensed in a suitable instrumentality, diagrammaticallyillustrated 5 and designated 36, collecting as liquid distillate in thedistillate receiver 31. This receiver may be provided with the usual gasrelief pipe 38, controlled by valve 39, and with liquid draw-off line40, controlled by valve 4I. Regulated portions of 55 the distillatelfrom the receiver 31 may be returned through the line 33, in which maylbe interposed the pump 42, to the dephlegmator.

A draw-off 43, controlled by valve 44, may be provided for withdrawingany condensate from the compartment formed between partitions 30 and 3iin the dephlegmator 1.

Returning to the reaction chamber 21, th non-vaporous residue may bewithdrawn through any one or more of the lines 45, in which may beinterposed valves 46, merging in a common header or transfer line 41.`This transfer line 41 may divert the residue through the line 48,controlled by valve 49, which line 48 communicates with the heatexchanger I4, from which the residuum may be Withdrawn through line 50,cooled in an instrumentality illustrated diagrammatically at 5|, andcollected in the residuum storage receptacle 52.

Or if desired,'the valve 43 may be totally or partially'closed -and allor a regulated portion of the residue diverted through the line 53,controlled'by valve 54, discharging into the interior of a flash chamber55. The valves 46, 49 and'54 are preferably pressure reducing valves, sothat the residue which has been withdrawn from the reaction chamber 21under the superatmospheric pressure maintained therein may have `itspressure considerably reduced or released altogether; thus, when beingintroduced to the flash chamber 55, a very substantial portion Aof itWill vaporize, due to its latent heat. Vapors which separate in theflash chamber 55 may pass out through the line 55, controlled by valve51, into the interior of the dephlegmator' 1,'Where theycombine with thevapors coming Vdirectly from the reaction chamber through vapor line 28,and are subjected to similar reflux condensation. It may be pointed outhere that the valve 29 in vapor transfer line 28 is preferably apressure reducing valve, in order that the high pressure maintained inthe chamber 21 may be considerably reduced or released altogether, sothat the dephlegmator 1 operates under a lower pressure than the tube 23and reaction chamber 21.

Reflux condensate collects in a body on the partition 30, as illustratedat 58, being withdrawn through the line 59 into the Vapor separator I8,so that the reflux from the dephlegmator and unvaporized charging stockare united and forwarded through the line 2| to the heating tube 2'3 forheating. Suitable liquid draw-offs are provided on the side wall of thedephlegmator, as illustrated diagrammatically at 6G, controlled byValves 6I, to determine the liquid level of reflux condensate for thepurpose of control. It, of course, is apparent that While I have shownthe dephlegmator 1 and Vflash chamber 55 as a Ysingle instrumentalityseparated by the partitions 30 and 3l, that they may be separateinstrmnentaIitieS, if found more desirable.

The arrangement is such that reboiling of the reflux condensatecollected in the pool illustrated vat 58 takes place dueto the heat ofthe vapors passing upwardly through the open-ended up- ,rights'32. f

`Residue rfrom the flash chamber 55 may be Withdrawn through the line 62diverted through .line 63,- controlled by valve 64, cooled in coolinginstrumentality designated 65, and collected in anyrsuitable storage,orvalve 64 may be closed and valvef in draw-off line 61 opened to divertDescribing now a feature of the present invention, I illustrate a numberof Ways for controlling 'the gravity of the residue withdrawn, whichcontrol is important in the production of a residue suitable for use asfuel. One method of controlling the gravity of the residue is, ofcourse, by control or variation of the pressure maintained in the flashchamber 55, which can be controlled, of course, by the valves sho-wn inthe drawing.

Or this gravity may be controlled by introducing a regulated portion ofthe raw oil directly into the residuum line at the point where theresiduum is released from the reaction chamber. This is accomplished bymanipulating the valve 68 in the branch 69, thus diverting a smallportion of the raw oil into the line 10, controlled by valve 1 I, whichmerges with the residue drawoff line 41 from the reaction chamber 21.This mixturerof a controlled quantity of the raw oil with the residuewithdrawn from reaction chamber 21 will lower the temperature of theresidue and thereby control the amount of vapors released in the flashchamber 55.

Or as an alternative, a portion of the raw oil feed, before passingthrough the pre-heating coil 6 in the top of the dephlegmator can bediverted through the cooling coil 12, located in the upper section ofthe flash chamber 55, having connecting lines v13, controlled by valves14, so as to condense some of the heavy 'ends of the vapors released inthe flash chamber 55, thus changing the gravity of the withdrawnresidue.

As another feature of the invention, the vapors being introduced intothe dephlegmator 1 through the vapor -line 28, on account of beingreleased from the high pressure maintained in the Vreaction chamber 21,will be in a superheated state, and possibly from 100 to 150 higher intemperature than they normally Would be if vaporized at the pressurecarried in the dephlegmator. This heat is available for heating thereflux collecting in the pool 58, thus stripping any light ends in thereflux and permitting only the heavier ends of the reflux to bewithdrawnthrough the pipe 59 and returned to the cracking tubes 23.V Forthe purpose of diverting reflux, if for any reason it should be founddesirable, I provide the emergency line 15, controlled by valve 16.

It lwill be apparent to those vskilled in the Vart that suitableapparatus for carrying out the invention diagrammatically illustratedinthe drawing is to be used. The plant may be operated to produce alarge yield of residual oil suitable for use as fuel, the gravity ofwhich canbe very carefully controlled, and a low yield of gasoline,while also permitting by obvious manipulation an operation and processto -be carried on, in which a low yield of residue is produced and ahigh yield of gasoline. In case a large .yield of residue is produced,itis advisable to-pre-heat the incoming raw oil in the coil I3 by meansof the outgoing residue. Should it be found desirable to by-.pass

the coil I3, the valves I2 and I6 are closed and the valve 11 in line'18 opened. If it should be found desirable topartially pre-heat the rawoil being diverted through theline A1li to mix with the residuewithdrawn through the liner 41, the valve 19I in line v80 may bemanipulated to pass the preheated raw oilinto the line 10. A branch8Icontrolled by valve 82 also permits the raw oil after it has beenpre-heated by passing through the closed coil-6 lto bediverted yintothelinel.

It mayin Ysome instances be desirableto makev in this plant a so-callednon-residuum run,

that is, with a maximum yield of vapors which are condensed intogasoline-like products, and a minimum or negligible production of liquidresidue, it being the purpose to convert the charging stock mainly intotwo products, vapors and a substantially non-flowing coke-like residue.In such an instance, it may be found desirable anyway to flash theresidue from reaction chamber 21 in the flash chamber 55 and relieve itof its light fractions in the form of vapors, in order to avoid adecrease in the capacity of the plant.

In order to permit such an operation, I provide additional draw-offsfrom the flash chamber 55, designated 83 and 84, respectively,controlled by valves 85 and 86. The proper manipulation of valves 85 and86 will divert controlled quantities of the residue through the line 81,in which may be interposed a hot oil pump 88, returning the residueeither through a continuation 89 of the line 81, controlled by valve 9D,to the transfer line 25, or diverting same through the branch 8 I,controlled by valve 92, directly into the reaction chamber 21.

In operating the plant for this purpose, it is desirable that thesmallest deposit of coke be had in the flash chamber 55, while most ofthe carbon will collect in the reaction chamber 21. Some coke maydeposit in the flash chamber 55, hence I have illustrated the additionaldraw-off 83 at a Yhigher level, which it is to be understood may beutilized for either returning the residue to the line 81, or passing itto storage through the line 48 by obvious manipulation of valves.

From the foregoing, it will be apparent that I have perfected a veryefficient and scientifically designed method, in which any type ofcharging stock differing widely in characteristics may be handled, andwhich method may be carried out under any desired efficient operatingconditions to produce a maximum yield of the type of product desired.The flexibility of the plant has been emphasized in the foregoingdescription.

I claim as my invention:

1. In the art of hydrocarbon oil conversion, steps which comprisesubjecting hydrocarbon oil to cracking conditions of temperatur-e andsuperatmospheric pressure, discharging the heated oil into an enlargedzone where substantial vaporization occurs, separating the vapors fromthe nonvaporous residue, in removing said separated vapors andsubjecting same to cooling action, separately withdrawing thenon-vaporous residue, substantially reducing the pressure maintained onsaid non-vaporous residue and passing same to a zone where vaporizationis effected due to sensible heat, separating resultant vapors andseparately withdrawing the remaining non-vaporous residue fromthevsecond mentioned zone and returning portions thereof to said heatedoil prior to vaporization thereof.

2. In the art of hydrocarbon oilconversion, steps whichcomprisesubjectinghydrocarbon oil to cracking conditions of temperature andsuperatmospheric pressure, discharging the heated oil into an enlargedzone where substantial vaporization occurs, separating the vapors fromthe non-vaporous residue, in removing said separated vapors andsubjecting same to cooling action, separately withdrawing thenon-vaporous residue, substantially reducing the pressure maintained onsaid non-vaporous residue and passing same to a zone where vaporizationis effected due to sensible heat, separating resultant vapors andseparately withdrawing the remaining non-vaporous residue from thesecond mentioned zone and returning portions thereof to said heated oilprior to vaporization thereof, combining the vapors from the crackingand flash distillation steps, subjecting them to common deplegmation andfinal condensation.

3. In the art of hydrocarbon oil conversion, steps which comprisesubjecting hydrocarbon oil to cracking conditions of temperature andsuperatmospheric pressure, discharging the heated oil into an enlargedzone where substantial vaporization occurs, separating the vapors fromthe nonvaporous residue, in removing said separated vapors andsubjecting same to cooling action, separately withdrawing thenon-vaporous residue, substantially reducing the pressure maintained onsaid non-vaporous residue and passing same to a zone where vaporizationis effected due to sensible heat, separating resultant vapors andseparately withdrawing the remaining non-vaporous residue from thesecond mentioned zone and returning portions thereof to said heated oilprior to vaporization thereof, combining the vapors from the crackingand ash distillation steps, subjecting them to common deplegmation andnal condensation, cooling the vapors in said deplegmation step bypassing charging cil in indirect heat interchange relation out ofphysical contact therewith, and returning the final condensate in directphysical contact therewith.

4. A hydrocarbon oil conversion process which comprises heating chargingoil for the process to distillation temperature and introducing the sameto a vapor separating zone wherein vapors are separated from unvaporizedoil, introducing the vapors to a fractionating zone containing vaporousproducts formed as hereinafter set forth, fractionating the commingledvapors in the fractionating zone to condense heavier fractions thereof,combining resultant reflux condensate with unvaporized portion of thecharging oil separated in said separating zone, subjecting the thuscommingled oils to cracking conditions of temperature and pressure in aheating coil and then discharging the same into a second separating zonemaintained under pressure, separately removing vapors and liquid fromthe second separating zone and ash distilling the liquid by pressurereduction in a flashing zone independent'of said separating zones andcommingling residual oil from the ashing zone with the heated productsdischarging from said coil into the second separating zone, introducingresultant flashed vapors from the flashing zone and vapors removed fromthe second separating zone to the fractionating zone as said vaporousproducts, and finally condensing the fractionated vapors.

CARBON P. DUBBS.

